Lay-in duct having side-bracing and wire-retaining means



March 18, 1969 D. G. FISCHER ET AL-- 3,433,270

LAY-IN DUCT HAVING SIDE-BRACING AND WIRE-RETAINING MEANS Filed Oct. 13, 1966 DONALD a. FISCHER m m m CLIFFORD w. JONES (fiJl/hfl w United States Patent 1 Claim This invention relates generally to lay-in duct for electrical power distribution wires, and more particularly to lay-in duct having means for bracing the sides thereof and for retaining wires therein when the duct is installed in other than a horizontal upright position.

An object of the invention is to provide channel-shaped lay-in duct having means for bracing opposed side wall portions thereof and for retaining wires therein.

In the drawings:

FIG. 1 is a perspective view of a section of lay-in duct constructed in accordance with the invention, a cover thereof being shown in a partially open position;

FIG. 2 is a fragmentary sectional view taken generally along the line 22 of FIG. 1, but showing the cover in a closed position;

FIG. 3 is a side elevational view of a side wall bracing and wire retaining means of the lay-in duct of FIG. 1;

FIG. 4 is a bottom view if the side wall bracing and wire retaining means of FIG. 3;

FIG. 5 is a sectional view taken generally along the line 5-5 of FIG. 3;

FIG. 6 is an enlarged fragmentary sectional view taken generally along the line 66 of FIG. 4 but showing a portion of a side wall of the duct of FIG. 1 in phantom and showing a leg portion of the bracing and retaining means of FIG. 3 in a straightened position; and

FIG. 7 is an enlarged fragmentary sectional view taken generally along the line 77 of FIG. 1.

The present invention relates to an improvement on the lay-in duct shown and described in copending application, Ser. No. 339,246, filed Jan. 21, 1964, now Patent No. 3,312,251, issued Apr. 4, 1967, to which reference may be had for a more complete description of the basic duct.

FIG. 1 shows a channel-shaped duct 10 including a bottom wall portion 10a and a pair of opposed generally parallel side wall portions 10b and 100. A cover 12 is pivotally mounted on the side wall portion 10b.

In accordance with the invention, a bracing and wire retaining member 14 is mounted on the side wall portions 10b and 10c, which are provided with a plurality of opposed pairs of elongated indentations 10d spaced longitudinally of the duct 10. The indentations 10d are formed by partially shearing the side wall portions 10b and 100 inwardly so as to provide shoulders facing the bottom wall portion 10a but disposed on the outer surfaces of the side wall portions 10b and 10c, as shown in FIG. 2.

A plurality of bracing and wire retaining members 14 may be mounted in spaced relationship longitudinally of the duct 10, one at each pair of the opposed indentations 10d.

Each member 14 includes an elongated generally rectangular main body portion 14a strengthened by the formation of a rib 14b thereon. Each member 14 also includes four outer leg portions 14c and two inner leg portions 14d extending generally at right angles to the body portion 14a, two of the leg portions 140 and one of the leg portions 14d being disposed adjacent each of the opposite ends of the body portion 14a. The two leg por- 3,433,270 Patented Mar. 18, 1969 tions 14c at each end of the body portion 14a are spaced on opposite sides of the leg portion 14d laterally of the body portion 14a. Longitudinally of the body portion 14a, the leg portions 140 at opposite ends of the body portion 14a are spaced farther apart than the leg portions 14d. The leg portions 140 are longer than the leg portions 14d, and each leg portion 14c is provided with an inwardly projecting portion 14e partially sheared from the remainder of the leg portion to provide a shoulder facing the body portion 14a.

As shown in FIG. 7, each elongated indentation 10d is provided adjacent opposite ends with a pair of camming surfaces 10e.

When a bracing and wire retaining member 14 is installed on a duct 10, it must be anchored securely in place, and yet it must be readily removable if the lay-in feature of the duct, by which wires may be laid in the duct transversely rather than fished through the duct longitudinally, is not to be destroyed.

The unstressed condition of one of the members 14 is shown best in FIG. 3, wherein the leg portions 140 are inclined slightly toward each other. The members 14 may be installed by pushing them into place on the side wall portions 10b and 10c at the locations of the indentations 10d, the free end portions of the leg portions 14d also being inclined toward each other for easier entry of the sidewall portion 10b or 10c between the leg portions 140 and 14d. When a member 14 is installed in place, the side wall portion 10b is between the leg portions 14c or 14d adjacent one end of the member 14, and as shown in FIG. 6, the side wall portion is between the leg portions 14c and 14d adjacent the other end of the member 14. The free end portions of the side wall portions 10b and 100 are thus braced against movement both toward and away from each other, and wires (not shown) in the duct 10 may be retained therein by the members 14 in situations in which the duct 10 is installed in other than a horizontal upright position. Further, the members 14 are held securely in place by the disposition of pairs of the inwardly projecting portions 14e respectively in the indentations 10d. However, when it is desired to remove a member 14 from the duct 10, the member 14 may first be pushed longitudinally of the duct 10 in either direction, whereby one of the camming surfaces 102 of each indentation 10d moves the respective pair of inwa-rdly projecting portions 142 outwardly to a position in which they merely engage the outer surface of the respective side Wall portion 10b or 10c next to the respective groove 10d. The member 14 may then be pulled off the duct 10 in a direction perpendicular to the bottom wall portion 10a.

We claim:

1. A lay-in duct for receiving electrical wires, said layin duct comprising an elongated channel-shaped duct having a bottom wall and a pair of opposed generally parallel side walls, and an elongated side-bracing and wire-retaining member extending transversely of said duct and disposed opposite said bottom wall adjacent free end portions of said side walls, each of said side walls being provided on an outer surface thereof with an indentation opposite an indentation on an outer surface of the other of said side walls, each of a pair of opposite end portions of said member being provided with an outer leg portion engaging an outer surface of a respective one of said side walls and an inner leg portion engaging an inner surface of the respective one of said side walls, each of said outer leg portions being provided with an inwardly projecting portion received in a respective one of said indentations, each of said side walls being provided on an outer'surface thereof with a shoulder defining an edge of the indentation therein and facing toward said bottom wall, each of said inwardly projecting portions of said outer leg portions being provided with a shoulder facing the shoulder of the respective side wall, and each of said side walls being provided on an outer surface thereof with a camming surface forming an end of the indentation therein in a direction longitudinally of said duct, whereby said member may be removed from said duct by first moving the member longitudinally of said duct to force said inwardly projecting portions respectively out of said indentations by means of said camm'ing surfaces and then pulling said member off said duct in a direction generally perpendicular to said bottom wall.

References Cited UNITED STATES PATENTS 1/1959 Huehnel 138-157 X 1/1960 Caveney 1'38--157 2/1967 Finniger 1-38-1'62 4/1967 Marks et a1 138-158 FOREIGN PATENTS 1876 Great Britain.

US. Cl. X.R. 

1. A LAY-IN DUCT FOR RECEIVING ELECTRICAL WIRES, SAID LAYIN DUCT COMPRISING AN ELONGATED CHANNEL-SHAPED DUCT HAVING A BOTTOM WALL AND A PAIR OF OPPOSED GENERALLY PARALLEL SIDE WALLS, AND AN ELONGATED SIDE-BRACING AND WIRE-RETAINING MEMBER EXTENDING TRANSVERSELY OF SAID DUCT AND DISPOSED OPPOSITE SIDE BOTTOM WALL ADJACENT FREE END PORTIONS OF SAID SIDE WALLS, EACH OF SAID SIDE WALLS BEING PROVIDED ON AN OUTER SURFACE THEREOF WITH AN INDENTATION OPPOSITE AN INDENTATION ON AN OUTER SURFACE OF THE OTHER OF SAID SIDE WALLS, EACH OF A PAIR OF OPPOSITE END PORTIONS OF SAID MEMBER BEING PROVIDED WITH AN OUTER LEG PORTION ENGAGING AN OUTER SURFACE OF A RESPECTIVE ONE OF SAID SIDE WALLS AND AN INNER LEG PORTION ENGAGING AN INNER SURFACE OF THE RESPECTIVE ONE OF SAID SIDE WALLS, EACHOF SAID OUTER LEG PORTIONS BEING PROVIDED WITH AN INWARDLY PROJECTING PORTION RECEIVED IN A RESPECTIVE ONE OF SAID INDENTATIONS, EACH OF SAID SIDE WALLS BEING PROVIDED ON AN OUTER SURFACE THEREOF WITH A SHOULDER DEFINING AN EDGE OF THE INDENTATION THEREIN AND FACING TOWARD SAID BOTTOM WALLS, EACH OF SAID INWARDLY PROJECTING PORTIONS OF SAID OUTER LEG PORTIONS BEING PROVIDED WITH A SHOULDER FACING THE SHOULDER OF THE RESPECTIVE SIDE WALL, AND EACH OF SAID SIDE WALLS BEING PROVIDED ON AN OUTER SURFACE THEREOF WITH A CAMMING SURFACE FORMING AN END OF THE INDENTATION THEREIN IN A DIRECTION LONGITUDINALLY OF SAID DUCT, WHEREB Y SAID MEMBER MAY BE REMOVED FROM SAID DUCT BY FIRST MOVING THE MEMBER LONGITUDINALLY OF SAID DUCT TO FORCE SAID INWARDLY PROJECTING PORTIONS RESPECTIVELY OUT OF SAID INDENTATIONS BY MEANS OF SAID CAMMING SURFACES AND THEN PULLING SAID MEMBER OFF SAID DUCT IN A DIRECTION GENERALLY PERPENDICULAR TO SAID BOTTOM WALL. 